#include <bits/stdc++.h>
#include<atcoder/modint>
#define int long long
using namespace std;
using mint=atcoder::modint1000000007;
int inf=1e18;
signed main(){
    int n,s,k;cin>>n>>s>>k;
    vector<vector<mint>>dp(n+1,vector<mint>(s+1));
    for(int i=0;i<=s;i+=n){
        dp[1][i]=1;
    }
    for(int i=2;i<=n;i++){
        int mult=n+1-i;
        for(int t=0;t<=s;t++){
            if(t>=k*mult){
                dp[i][t]+=dp[i-1][t-k*mult];
            }
            if(t-mult>=0){
                dp[i][t]+=dp[i][t-mult];
            }
        }
    }
    cout<<dp[n][s].val()<<endl;
}